These are the commercial jet engines you see, like the Boeing 777, 747, Airbus A330 and A380s. Though there is a considerable reduction of the engine thrust, at these altitudes the lower drag associated with low air density means a more economical flight with a higher True Air Speed.
Crepitus in the knees may be caused by knee injuries such as meniscus tears. These are fairly common in people who play sports, jog, or run. A meniscus tear can cause crepitus as the joint moves. Chondromalacia patella is a dull ache behind the kneecap, usually caused by overuse or injury. There will be damage to the undersurface cartilage covering the kneecap.
Prepatellar bursitis (also referred to as patellar bursitis) is a painful condition affecting the front of the kneecap (patella). The prepatellar bursa is usually very thin and serves as a cushion between the patella and your skin, protecting your kneecap and the soft tissue that holds it is place.Prepatellar bursitis causes knee pain at the front of the knee due to the bursa sac becoming irritated and inflamed.This bursa is just one of many bursae (plural for bursa) in your body. Bursae are sacs of synovial fluid that are rich in protein and collagen.he prepatellar bursa is usually very thin and serves as a cushion between the patella and your skin, protecting your kneecap and the soft tissue that holds it is place. Prepatellar bursitis causes knee pain at the front of the knee due to the bursa sac becoming irritated and inflamed.